@article{ISU_2005_5_1-2_a6,
     author = {V. A. Yurko},
     title = {Recovering singular differential pencils with {\cyra} turning point},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {71--81},
     year = {2005},
     volume = {5},
     number = {1-2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ISU_2005_5_1-2_a6/}
}